1. Field of the Invention
The invention relates to a surgical forceps with a forceps jaw, with a handle consisting of two grip parts with which the one first grip part is connected to a forceps housing and the other second grip part is pivotable for opening and closing the jaw mouth, with an adjustment rod which is distally and proximally adjustable for opening and closing the forceps jaw and whose proximal end has a connection to a limb of the two-limbed second grip part, and with at least one wound spring element as an overload protection against the breakage of jaw parts.
2. Description of the Prior Art
In order for example with the excision of samples to be able to securely grasp tissue and to separate this cleanly from the remaining tissue, high forces must be transmited onto the cutting edges of the jaw parts of a surgical forceps. With a pressure of the jaw parts which is too slight the tissue is not correctly separated which may lead to the fact that incompletely separated tissue may be torn off. With a pressure on the jaw parts which is too greatxe2x80x94brought about via the handle of the forcepsxe2x80x94there exists the danger that parts of the forceps may break. In both cases there therefore exists the danger that the patient is endangered or is injured. For the unexperienced operator it is also difficult to meter the required force on the grip part so that on the one hand the tissue is cleanly severed, but that on the other hand the forceps is not damaged.
DE 36 01 166 C2 and DE 299 17 554 U1 disclose therefore in each case a surgical forceps of the known type with which the transmission of the force exerted on the handle is effected via a spring integrated into the forceps in the form of a helical spring. The forceps is thus secured from overload.
With a surgical forceps according to DE 299 17 554 U1 it is however disadvantageous that the spiral spring provided here must have a large construction, i.e. a large diameter and a great length in order to achieve the desired overload securement. With this inevitably the size and the weight of the forceps increases. Furthermore with this forceps it is provided that with a loading the whole forceps shank with the jaw part displaces in the direction of the jaw part which is not favorable for the positioning of the jaw part. Furthermore this forceps comprises a multitude of individual components which is why it is expensive.
The solution according to DE 36 01 166 C2 has to the same extent a large construction and on account of design by way of the overload securement has a great length which in the same manner leads to difficulty in handling.
Another surgical instrument known from DE 298 06 799 U1 as an overlaod protection applies a buffer consisting of rubber elastic material which is shaped in an annular manner and is installed into a hollow-cylindrical holder. With this although a smaller and lighter construction is possible it is however disadvantageous here that the buffer of elastic material may age by which means its spring property is lowered. Furthermore there also arise problems with the cleaning and sterilization of the forceps since the region of the buffer is difficultly accessible.
It is therefore the object of the invention to further develop a surgical forceps of the initially mentioned type such that the mentioned disadvantages are avoided, in particular by way of a special design of the spring element or spring elements and its or their arrangement. The forceps is thus to have as small and as compact as possible construction and not be significantly heavier than previously known forceps without overload protection. The parts of the overload securement are to be easy to clean and sterilise. The forceps concept is further to be able to be simply adaptable to the various demands of the effect of the overload securement. Finally the construction of the forceps is to be simpler than is the case with the state of the art so that also the manufacturing costs for the forceps may be reduced.
The solution of this object of the invention is characterized in that the spring element consists of a flat serpentine-shaped material with windings lying in one plane. In contrast to the state of the art thus there is provided in principle a different construction of the spring element.
Preferably the spring element connects one limb of the second grip part directly to the proximal end of the adjusting rod. At the same time the forceps may be designed such that alternatively in the case of overload the spring element acts as a tension spring or as a compression spring.
It may also be provided that the forceps jaw is opened against the effect of a compression spring located in the forceps housing, wherein the compression spring which is formed as a helical spring and which runs through the adjusting rod is arranged in a sleeve adjustable axially in the forceps housing on pivoting the second grip part, and which with its one end is supported on the base of the sleeve open at one end and with its other end is supported on a shoulder in the forceps housing.
A particularly simple construction results when the two ends of the spring element in each case are formed as a knuckle eye, wherein the knuckle eyes in each case are connected byway of a joint pin on the one hand to the adjusting rod and on the other hand to the limb of the second grip part.
The respective neighbouring limbs of the spring element windings may run parallel or diverge in the direction of the connection webs connecting them or converge in the direction of the free space of the winding.
An influencing of the spring stiffness may be achieved in that there are connected at least two spring elements in parallel and arranged next to one another with knuckle eyes flush at their ends. The danger of the jamming of a finger in the spring elements is avoided in that in this case two windings of a spring element in relation to the windings of the spring element arranged next to it run displaced by half the width of a winding.
The spring elements may be easily assembled and dismantled when in the forceps housing and in the limb of the second grip part there are provided recesses open at the top for accommodating the spring elements.
The spring elements consist e.g. of spring steel, in particular of a TiNi alloy. With regard to the manufacturing possibility it is to be noticed that a simple and economic manufacture is given when the spring elements are either manufactured with the laser cutting method, by punching or with the erosion method, wherein a metal plate of initial material is used.